Weird Error message

[Sage]

Does anybody know what this error message means?

"X A problem is preventing Windows from accurately checking the license for this computer. error code 0x8009001d"

It appeared on a reboot, and after an additional reboot it has not reappeared.

 

[matty T]

this error might have happened if you installed the windows Xp Sp1

 

[Sage]

Not SP1

SP1 has not been installed on this machine, nore has there been any MS updates since April 2002.